Question

If the last number is even, the entire number is even in base 10. Why?

Answer 1

its saying 123456 is even bcos 6 is even.we know this to be true.

Answer 2

if we have more than one digit in our number than we have multiples of 10 in our number
and then a "remainder" of what ever is left in our 1's spot. For sure any multiple of 10 is even, thus we need the number in our 1's spot to be even.